Applicant has already described in its French patent application No. 82 08464 and in U.S. application Ser. No. 366,707 the disclosures of which are incorporated herein by reference, a connector using such mechanical locking for immobilizing an optical fiber in a centered position in a connector ferrule.
The connector described in the prior application, and for which the process according to the present invention can also be used, is of the type having two male ferrules mounted at the ends of the fibers to be connected, and a female reconstitution or aligning connector having a longitudinal bore to support and align the two ferrules face to face.
The female connector comprises, at its axial center within the longitudinal bore, an abutment body for the male ferrules, specifically, a sphere, having a through axial opening and a contact shoulder facing each of the male ferrules. Each male ferrule has an axially extending tubular projection extending into the opening of the abutment body and a conduit or passage into which the optical fiber can be introduced with play, and immobilized so that its end coincides with the end of the projection. Spaced from the end of the projection is an annular groove whose wall defines a contact support engaging the support shoulder of the abutment body of the female connector. These contact supports are axially pressed against the shoulders of the abutment body and cooperate with each other so that, during any relative movement of the shoulders and contact surfaces, the end of a fiber at the end of the male ferrule is maintained at a constant predetermined distance from the center of the abutment body.
In the above mentioned French patent application No. 82 08464, and U.S. application, each of the male ferrules comprises a ferrule body with an annular recess at its end and an interior tubular element, preferably metallic, particularly of steel, placed in a corresponding axial opening of the ferrule body and the end of which constitutes the projection. The mechanical locking means to immobilize the interior tubular element in the ferrule body, take the form of a plurality of small ball bearings forced into the corresponding radial holes of the ferrule body, and press against the interior tubular element.
As described in the prior patent application, the inner element is displaced radially in the ferrule body by micro-displacements of the force fit ball bearings in the radial holes of the ferrule body to bring the center of the optical fiber into coincidence with the axis of the abutment, while the annular groove of the ferrule body, which can be conical, engages the spherical body to center the ferrule.
The forces required to displace the ball bearings are highly dependent on the force fit between each ball bearing and the radial hole in which it is engaged, which leads to very close tolerances in manufacture as well as requiring very good surfaces on both the ball bearings and the radial holes. In addition, it is not always certain that the ball bearings forced into the radial holes, completely immobilize the inner tubular element with respect to the ferrule body.
The radial position of the fiber must in practice be precise within two micrometers, so that the displacement of the ball bearings must be done with at least the same precision.